A massive iceberg measuring about 50 miles by 17 miles is traveling toward the southern tip of South America at speeds of eight to 10 miles a day and is threatening to block shipping lanes. The iceberg, known as B-10A, broke away from Antarctica in 1992; some scientists attribute this break-up of Antarctic ice to climate change. A spokesperson for Chile’s Antarctic Scientific Institute said global warming was no doubt contributing “to the disintegration of the ice.”